Pirating is not really much cheaper TBH…my media server, including power, has to run for something like 6-7 years without upgrades or repairs to break even with what Netflix would cost in that same time frame. It’s not about saving money, it’s about not giving it to them.
Running a media server with bulk storage from an external HDD is just a terrible experience and recipe for issues, and doesn’t give a nice experience with a full library to select from at a whim anywhere in the world (like what streaming provides). Also, depending on library size, not even possible.
I have ~20tb of media on my server, which isn’t even that much, no chance that’ll run well in that configure you mention. It’s by no means a beefy server either, it’s a small ITX mobo in a case with a shitload of HDD bays.